Singlet oxygen species induced by colloidal crystalline carbon nitride induced for efficient H2O2 synthesis with in situ antibacterial effect

Solar-driven hydrogen (H 2 ) and hydrogen peroxide (H 2 O 2 ) generation over visible-light responsive carbon nitride (CN) photocatalysts for in situ efficient sterilization is a promising and eco-friendly strategy. Herein, a colloidal potassium-ion (K + ) intercalated crystalline CN nanosheets (KCCN) photocatalyst was constructed for boosting synergetic H 2 O 2 synthesis with isopropanol (IPA) oxidation and in situ antibacterial effect . The surface hydroxyl (−OH) and cyano (−C N) groups induced by molten salt (KCl)-assisted thermal treatments contributed to the colloidal nature of CN, facilitating for high wettability of KCCN in aqueous solution to gain active hydrogen (H + ) from water sustainably. Meaningfully, the enhanced high-energy singlet oxygen species ( 1 O 2 ) produced by KCNN-2 were verified by electron paramagnetic resonance (EPR) and 9,10-anthracenediyl-bis(methylene)-dimalonic acid (ABDA)-fluorescent probe, significantly contributing to H 2 O 2 production and antibacterial effect. Consequently, the optimal KCCN-2 exhibited a much enhanced H 2 generation of 4.11 mmol g −1 h −1 , and H 2 O 2 production activity of 1.82 mmol L −1 h −1 with acetone yield rate of 47.3 mmol g −1 h −1 under visible-light (λ > 420 nm) irradiation in 10 vol% IPA solution. The in-situ generated H 2 O 2 can be activated to produce reactive oxygen species (ROS), especially 1 O 2 , to effectively kill the Escherichia coli , reaching an improved an antibacterial rate of 89.7% under stimulated sunlight irradiation in 1 h. This work could offer a new insight into the photoinduced ROS for aqueous H 2 O 2 photosynthesis and antibacterial application.